mtd: nand: gpmi: get correct free oob space

change the way to calculate pagesize to get correct free oob space for
legacy_set_geometry function.
Signed-off-by: Han Xu <han.xu@nxp.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/gpmi-nand/gpmi-nand.c

@@ -318,7 +318,8 @@ static int legacy_set_geometry(struct gpmi_nand_data *this)
 		return -EINVAL;
 	}
 
-	geo->page_size = mtd->writesize + mtd->oobsize;
+	geo->page_size = mtd->writesize + geo->metadata_size +
+		(geo->gf_len * geo->ecc_strength * geo->ecc_chunk_count) / 8;
 	geo->payload_size = mtd->writesize;
 
 	/*